Cameras can be used to monitor the occurrences of various events, and the monitoring function of cameras is widely applied to, for example, traffic surveillance, supermarket surveillance, or community surveillance, and the like.
During surveillance using cameras in a monitoring device, if a sound-making surveilled object in the surveillance images (i.e., an image of the sound-making surveilled object is visible in the surveillance images) is relatively far from the monitoring device, the monitoring device cannot clearly collect the sound from the surveilled object, and thus the surveillance information is not complete.